Reading back my ramble post on this thread, I'm glad I've written down the information I collected somewhere.
Assuming we do switch shirt sponsor. If United's trampy, out of the way training campus and training kit sponsorship was worth £15m in 2014, without selling off the naming rights to the old toilet:
How much could City get for their stadium naming rights, state of the art training ground(which attracts tourists itself) and training kit sponsorship, once it's split off in 2021 or beyond? £30m seems fair.
Isn't it dodgy, how soon after City signed their "controversial deal" in 2011, United suddenly sign an inflated shirt sponsorship and an inflated training ground sponsorship a couple of years later? £80m a season combined, while they were on the slide, playing trash football. They can say "This is Manchester United" all they like, it simply doesn't add up. That's way more than £45m a season, and comfortably more than the increase to £65m which some believe occurred a few years back and they weren't even offering as much.
Next time any journalist or rival fan trots out inflated deals and "unlimited funds", I'm going to point out what happened in 2014, along with what UEFA's auditors said about the Etihad deal that same year.